# All Questions

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### What is the most massive object in the ISS whose position was altered by the circulating air?

In Leo S's comment to the question, Do astronauts develop the ability to regularly place an object at rest inside the ISS after extended periods in microgravity?, he said "forces due to circulation of ...
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### Are there any images of Curiosity during the sky crane operations?

This answer has a nice video of Curiosity's descent to MARS. The images come from the Mars Descent Imager (MARDI), which is mounted on the underside of the rover. Was there any camera mounted on the ...
21 views

### Defining overshoot and undershoot boundary of entry corridor

I have been reading up on the mathematic of atmospheric entry. I have found different methods to theoretically calculate the corridor width but I don't understand how to define the overshoot and ...
71 views

### Will the Mars 2020 rover be able to record high-framerate video of its helicopter?

According to this answer, there have been no instances of video recorded from beyond lunar orbit. Mostly, this makes sense as rovers and spacecraft are served just as well with pictures and nothing ...
78 views

### What Safety procedures include while orbit insertion, etc?

1)When a body is launched aboard a Rocket what are the safety parameters after 100 Km (Karman Line). 2) How does payloads not gets damaged from the billions of micrometeoroids?
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### How many “main” batteries does the ISS have? How many are still nickel-hydrogen?

CBS News's Third all-female spacewalk completes job of swapping out batteries says: NASA is in the process of replacing 48 older-generation nickel-hydrogen batteries in the station's solar power ...
107 views

### Spacecraft remaining at station-keeping with respect to the ISS

If any spacecraft has remained at station-keeping with respect to the ISS for 12 hours or more, how far from the station did the craft remain?
112 views

### How do ISS astronauts keep proficient on capsule procedures in long duration missions?

Before astronauts and cosmonauts go to the ISS they have months of simulator training on Soyuz spacecraft procedures for launch, rendezvous, docking and re-entry. Yet, once they are on the ISS they ...
48 views

### Getting the Velocity Vector in an Elliptical Orbit

I have a 2-D two body set up. I am using the vis-viva equation to get the velocity scalar of my elliptical orbit. I have the Semi-Major Axis, the radius, the eccentricity vector. I am sure I can ...
106 views

### What is a lithium fed GIT? How does it work?

This answer to What is the maximum speed an ion engine can propel a spacecraft at? mentions the following: Lithium fed GIT (gridded ion thrusters) have demonstrated 50,000 - 80,000 seconds of ISP (...
2k views

### After Crew Dragon launch abort, was Falcon 9's detonation intentional?

On 2020 January 19 SpaceX launched the Crew Dragon capsule and tested an in-flight abort, where the capsule separated from the Falcon 9 shortly after launch. Many headlines claim that the Falcon 9 ...
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### Designing Atmospheric Composition of a Fictional Gas Dwarf

I'm working to design a fictional artificially-engineered planet inspired by Venus (let's call it Cael) with an atmospheric layer/band 75 km above the surface that is effectively Earthlike, to the ...
117 views

### How can you determine the nature of an object from its flight path angle, velocity, and radius alone?

Assuming that a defense system is capable of determining an object's flight path angle ($\gamma$), velocity (v), and radius (r), how could one differentiate between an ICBM, a satellite, or a solar ...
6k views

### Why was the SpaceX abort test not initiated by real booster failure?

Today (2020-01-19) SpaceX had a successful flight abort test. As far as I can understand, at a specific altitude, Crew Dragon fired its engines and escaped from the rocket. This test looks like a ...
8k views

### How does SPACEX capture such images?

I was watching Today's launch test by SpaceX and had a question pertaining to the method used for imagery of objects mid-air! Other than on-board cameras, what techniques do NASA and SpaceX follows ...
198 views

### How to make Martian soil [migrated]

My son wants to replicate some experiments and try to grow plants in Martian soil for his A-level science project. I know NASA have managed to produce soil that mimics Martian soil, however I also ...
125 views

### How does this large, flat antenna made from overlapping circles at Australia's Carnarvon Space Tracking Center work?

@Fred's comment links to the Australian Broadcasting Corporation's How the Apollo 11 Moon landing was achieved with the vital help of Carnarvon Tracking Station which links to their Carnarvon space ...
51 views

### Venus-Mars-Venus cycler?

Is it possible to create a cycler that can travel from Venus to Mars, then back to Venus? Using as little delta-V as possible. To expound a bit further, it would need to travel from Venus to Mars ...
533 views

### How big are the tidal accelerations within the ISS?

This question asks about placing an object at rest in the International Space Station. But the ISS is a large object, large enough that gravity will vary across it and cause tidal forces that can ...
87 views

### Satellite infrastructure for detecting early fires

What satellite infrastructure would be necessary to detect wildfires early enough to prevent the disaster in Australia from repeating? Is that possible at all given variable cloud cover? If so, does ...
225 views
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### Do astronauts develop the ability to regularly place an object at rest inside the ISS after extended periods in microgravity?

This image from the ESA prompted the question why the fruits at the bottom left were not floating. An online response claimed after an extended time on the ISS astronauts get used to placing ...
3k views

### Why aren't there any active space debris removal systems implemented currently?

As of July 2013, estimates of more than 170 million debris smaller than 1 cm (0.4 in), about 670,000 debris 1–10 cm, and approximately 29,000 larger pieces of debris are in orbit. Space debris poses ...
159 views

### Help understanding how these components of a Honeysuckle Creek dish antenna work

@Fred's comment links to the Curious Droid video How Australia Helped Save Apollo 13 and a little after 02:15 and 03:00 it shows ...
162 views

### How much of the printed materials (manuals, instructions etc.) were allocated for the crew's use in Space Shuttles?

Whilst watching youtube video of an occasional Soyuz spacecraft launch (Soyuz ТМА-19М in this case), I've noticed (at 8:07) this large bundle of books. Another video of TMA-16M flight at 39:40 shows ...
65 views

### How long does the SYLDA fairing stay in orbit after deploying?

For dual-manifest missions, Ariane 5 often uses the Système de Lancement Double or SYLDA system to encapsulate the lower of two stacked satellites. It can be seen in the following image encapsulating ...
155 views

### Are there active (as of 2020) developments in liquid-fuel tank technology?

This question was broken off from previous mega-question located here. I am aware of the broad liquid fuel tank types: V-2-style steel fuselage Integral steel Integral aluminum (with varying types ...
74 views

### Can you help me fill in the gaps in my liquid-fuel rocket propellant tank technology knowledge? [closed]

I am currently aware of the following types of propellant tank technology: Steel fuselage, used in the V-2/A-4 & other rockets of its era (essentially a plane body) Integral steel tanks, first ...
134 views

### What is the “floating dust” seen in the Starliner test landing colour footage?

The first Starliner landing was in the very early morning. The live coverage was only able to show infrared pictures of the descent, however NASA's documentation of the event includes a colour video ...
43 views

### Terraforming's other side [closed]

We know how to make Mars' climate similar to that of the Earth.And Earth's climate like Venus.Both involve Greenhouse effect. What would it take to do the other way round like, making Earth's climate ...
126 views

### Terraforming Mars - Concentrating the Sun's energy on Mars using a lens to have the same effect as moving closer to the sun

I just read an earlier question about changing the orbit of Mars to be more earthlike. This was shot down because of the massive amounts of energy/time required. So, if the problem has to do with the ...
88 views

### Would it be possible to make a bubbleworld in an asteroid?

Would it be possible to drill a bore hole into an asteroid, fill it with water tanks and use sunlight to blow a hole large enough to fit a rotating space station inside, seal it off and fill it with ...
1k views

### Apollo altitude vs rate-of-descent schedule

In the final phase of the Apollo landings, the commander would go into "P66 attitude hold" mode, where the computer maintained a steady rate of descent while allowing the commander to change the ...
64 views

### Controlling suicide burn landing location in a python simulation?

I recently asked a question in stackoverflow about Simulation of suicide burn in openai-gym's LunarLander. Sadly most of my assumptions about suicide burn implementaion were wrong but the answer given ...
88 views

### Help with Vector format N-body state transition matrix

[Update] This is for an on-board autonomous navigation system (3-dimensions, interplanetary) using a Kalman Filter. There is no target trajectory. I have the position and velocity measurement models ...
49 views

### How to find instantaneous mass of a central body that results in a given osculating orbit?

This question was underspecified, so I'm going to try again. Osculating orbital elements are Keplerian elements of a hypothetical orbit around a specified center which would be tangent to a specified ...
59 views

### How do two-line element sets handle rev numbers > 99,999?

In a two-line element set (TLE), five characters in line 2 -- columns 64-68 -- are for the rev number. (https://en.wikipedia.org/wiki/Two-line_element_set) But some satellites have been around the ...
86 views

### How well does polymer filament survive space radiation?

I am reading Medium.com's 3D Printing Is Going to Space and Made In Space is doing something very cool. However, the point of failure in a system like this seems to be the polymer strut itself - how ...
56 views

### Mass of a circumlunar power transmission line?

The most easily available power source on the Moon is solar power. This has the obvious drawback that the night is two weeks long, during which you would probably still need power for a base to ...
88 views

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### Cubesat/Nanosat dispensers/deployers costs

I’ m looking for informations about dispensers/deployers equipement costs and associated launch costs, espacially for 12U configurations and over. I’ve got price information on Tyvak 12U Deployer in a ...
141 views

### Which of the recently launched Starlink satellites is the coated one?

Does anybody of you experts know which of the recently launched Starlink satellites is the coated one? We are occasionally measuring their brightness and would like to compare uncoated vs. coated. ...
6k views

### Advantages of launching very large rocket while submerged, buoyant, in a body of water

I vaguely remember reading about some supposed advantages of launching very large rockets (Saturn size and larger) from underwater in an ocean or similar large body of water. I was recently reminded ...
116 views

### What is the benefit of rigid solar arrays over flexible ones?

I read somewhere that flexible arrays tend do waver when a satellite is rotated so it would make Earth observing satellites have 'fuzzy' pictures. But I also read that Hubble used a flexible array for ...
26 views

6k views

### How did the U.S.S.R manage to rotate the N-1 from horizontal to vertical?

The title says it all - but I heard that NASA considered horizontal integration for the Saturn V couldn't be considered, as lifting the rocket to a vertical position would require an immense ...
48 views

### Curiosity's drive wheel motors' manufacturer?

Although there are answers listed elsewhere on this site about the power requirements for the Curiosity Rover drive wheels, does anyone know what company provided those drive motors?
138 views

### Are the lines on the wheels of the Mars 2020 rover wavy? If so, why?

CNET's NASA narrows down Mars 2020 rover names: Hello, Fido? includes the image below. I'm not sure if the rover is moving and a rolling shutter was in use, or if the lines on the wheels are really ...
60 views

### Cubesat Launch Costs discussion still active? [closed]

I just discover this very interesting Cubesat Launch Costs discussion. Is it still active?